Have you checked out the veggie charts? It answers a lot of your questions:
https://www.guineapigcages.com/foru...g-nutrition-charts-poisonous-plants-list.html.
I've given green beans and pea pods, and I don't remove the peas or take apart the beans in any way. As for corn on the cob, I've heard it's rather fattening and is more of a treat.
We have our own garden for the family, but we added a few plants just for the pigs. We have parsley, basil, cilantro, squash, cucumber, bell pepper, strawberries, watermelon, and tomatoes. I've also done wheatgrass in a pan before. For some reason I always kill wheatgrass, though, so it hasn't work out too well. You can feed a variety of forages, which are also listed on those charts.
If you're not sure if it's safe to feed, stay on the safe side and don't feed it! Check the veggie charts first and stick to low calcium, high Vitamin C vegetables, but remember that variety is absolutely key!
Good luck!
